This invention relates to an imaging device.
EP-A-154962 describes an imaging device in the form of an image sensor comprising a first substrate carrying an array of photosensitive elements. In the image sensor described in EP-A-154962, each photosensitive element is associated with a respective lens element for focussing light incident on the lens element onto the associated photosensitive element. As described in EP-A-154962, the photosensitive elements are formed by thin-film technology on one surface of an insulating substrate and the lens elements are formed on the other surface of the same substrate by, for example, locally altering the refractive index of the substrate. In such a case, the focal length of the image sensor is of course determined by the construction of the lenses and in practice will be limited by the technology used to form the lens.